Concentric cylinder heat exchanger

ABSTRACT

A heat exchanger formed by a plurality of concentric tubes having annular spaces therebetween. Helical-shaped vanes having waves therein are disposed in the annular spaces. Interconnection means are provided to create fluidic paths through the annular spaces.

United States Patent 1 Lawson [451 Sept. 23, 1975 CONCENTRIC CYLINDERHEAT EXCHANGER [75] Inventor: Drew B. Lawson, Los Gatos, Calif.

[73] Assignee: The United States of America as represented by theSecretary of the Navy, Washington, DC.

[22] Filed: May 2, 1974 [21] Appl. No.: 466,351

{52] US. Cl. 165/156; 165/141; 138/38 [51] Int. Cl. F28D 7/00 [58] Fieldof Search 165/140, 141, 156;

[56] References Cited UNITED STATES PATENTS 2,300.57) 11/1942 Lenning138/38 X Carter 165/156 X Pearson 138/38 Primary ExaminerCharles J.Myhre Assistant E.\'aminerTheophil W. Streule, Jr. Attorney, Agent, orFirrr'1Rich1ard S. Sciascia; .I. M. St. Amand; D'arrell E. Hollis [57]ABSTRACT A heat exchanger formed by a plurality of concentric tubeshaving annular spaces therebetween. Helicalshaped vanes having wavestherein are disposed in the annular spaces. Interconnection means areprovided to create fluidic paths through the annular spaces.

3 Claims, 5 Drawing Figures I; ICONCENTRIC CYLINDER HEAT EXCHANGEIRSTATEMENT OF GOVERNMENT INTEREST The invention described herein may bemanufac tured and used by or for the Government of the United States ofAmerica for governmental purposeswithout the payment of any royaltiesthereon or therefor.

BACKGROUND OFTHE INVENTION 1. Field of the Invention- Thepresentinvention relates generally to heat exchangers and moreparticularly to concentric tube heat exchangers having waved,helical-shaped vanes.

2. Description ofthe Prior Art.

A heat exchanger is a device that transfers heat from one fluid toanother fluid..Large surface areas between fluids,- turbulence in thefluids, and fluids flowing in opposite directions enhance heat transfer.

There are a wide variety of heat exchangers in the prior art utilizingone or more helical paths. However, such prior art heat exchangers aredesigned for quick disassembly or easy cleaning with heat transfer beinga secondary consideration. Hence, such prior art heat exchangers do notmaximize the surface areas between fluids, nor cause fluids to flow inOpposite directions or create turbulence in the fluids.

SUMMARY OF THE INVENTION The general purposes of the present inventionare to provide a concentric tube heat exchanger that maximizes thesurface area between fluids, causes fluids in adjacent annular spaces toflow in opposite directions, and creates turbulence in the fluids. Toattain this, the present invention provides a plurality of concentriccylinders having annular spaces therebetween. Waved, helical-shapedvanes are disposed in the annular spacespManifolds at both ends of theconcentric cylinders contain the required flow passages necessary tocreate opposite fluid flow in adjacent annular spaces.

Accordingly, one object of the present invention is to provide fluidflow in adjacent fluid flow paths in opposite directions. I

Another object of the present invention is to induce turbulence in thefield in all fluid flow paths.

Another object of the present invention is to maximize the surface areabetween adjacent fluid flow paths.

Another object of the present invention is to maximize heat exchangeproperties.

Another object of the present invention is to maximize the efficiency ofheat exchange.

Another object of the present invention is to-provide improved andeasier maintenance.

Another object of the present invention is to provide economy offabrication and operation.

Othef objects and a more complete appreciation of the present inventionand itsmany attendant advantages will become apparent as the samebecomes better understood by reference to the following detaileddescription when considered in conjunction with the accompanyingdrawings wherein like reference numerals refer to like parts throughoutthe figures thereof and wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a specific embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a heatexchanger 10 having a cylindrical casing 12 and a series of concentriccylinders 14, I6, l8 20 and 22 enclosed therein. Annular space 24 isformed between cylindrical casing 12 and concentric cylinder 14. Annularspaces 26, 28, 30 and 32 are formed between concentric cylinders l4 andl6, l6 and 18, 18 and 20, and 20 and 22, respectively. Annu lar space 34is the innermost annular space and is formed by concentric cylinder 22.Annular space 24 is the outermost annular space. I

Manifolds 36 and 38 are connected to opposite ends of heat exchanger 10.Manifolds 36 and 38 provide in terconnections between annular spaces 24,26, 28, 30, 32 and 34 so .thatfluid paths 40 and 42- are'defined. Notethat fluid-path 40 is adjacent to and in an opposite direction fromfluid path 42'. Fluid path 40 begins at inlet 44 in manifold 36 andterminatesat outlet 46 in" manifold 38. Fluid path 42 begins at inlet 48in manifold 38 and terminates at outlet 50 in manifold 36.

Note that adjacent annular spaces have fluids flowing in opposite'directions,"as indicated by arrows 52, 54,

56, 58, 60 and 62. As will be discussed supra, manifolds j 36 and 38connectevery other annular space in series to define fluidic'paths 40and 42.

Now turning to FIG;'2, fluid paths 40 and 42 are illustrated. F165 2 isa'sectional view along lines 2-2 of FIG. 1.

FIG. 3 is a sectional view along lines 3 of FIG.

1 illustrating manifold 36. Fluid in fluid path 40 enters manifold 36 atinlet 44 and passes into annular space 24 through opening 72. The fluidthen passes down annular sp'ace 24 through manifoild 38Iof FIG. I andback down annular space 28. The-flluidjthen passes through opening 74and .76 in manifold 36 and into annular spaces 32. The fluid then passesdown annular space 32 throughmanifold 38 and =outlet 46 of FIG. 1. g

The fluid in fluid path 42 enters manifold 38 at inlet 48 of FIG. I. Thefluid flows down annular space 26, enters manifold 36 at opening 78, andexits manifold 36 at opening. 80 into .annularspace 30. The fluid thenpassesdown annularspace 30 through manifold 38 and back downannularspace 34. The fluid then exits manifold 3a through outlet 50.

Manifold38 is constructed with the requisite opcnings in like manner tomanifold 36. Also, additional concentric cylinders over the number shownin FIGS. 1, 2 and 3 may be utilized. Of course, larger manifolds withadditional openings will be required in order to correctly define theproper fluid paths.

Now turning to FIG. 4, helical-shaped vane 70, having wave-shapedsurfaces, and helical-shaped vane 72 are illustrated. Wave-surfaced,helical-shaped vane is disposed in annular space 28 between concentriccylinders l6 and 18. Helical-shaped vane 72 is disposed in annular space30 between concentric cylinders 18 and 20.

Looking along the longitudinal axis of heat exchanger in the directionindicated by arrow 80 in FIG. 4, vane 72 in annular space 30 proceeds ina clockwise direction, as noted by arrow 82, while vane 70 in adjacentannular space 28 proceeds in a counterclockwise direction, as noted byarrow 84. Placing the helical-shaped vanes in such manner creates across flow between the fluids in adjacent annular spaces. Arrow 100indicates the direction of flow of fluid in annular space 30. Arrow 102indicates the direction of flow of fluid in annular space 28.

The helical-shaped vanes create a large surface area over which fluidsin adjacent annular spaces flow, thus increasing the efficiency of heattransfer between the fluids in adjacent annular spaces. In addition, thewavesurfaced, helical-shaped vanes 70 impart turbulence to the fluid inannular space 28, thereby increasing the efficiency of heat transferbetween the fluids in adjacent annular spaces to an even greater extent.

It is noted that wave-surfaced, helical-shaped vanes are disposed inannular spaces 24, 26, 28, 30 and 32 of FIGS. 1, 2 and 3 to simplify thedrawings. Wavesurfaced, helical-shaped vane 70 in annular space 28 formsa fluid-tight seal at its top edge 90 with concentric cylinder 16 andits bottom edge 92 with concentric cylinder 18. Of course, in likemanner, all helicalshaped vanes in heat exchanger 10 are so sealed totheir respective concentric cylinders.

Nowturning to FIG. 5, wave-surfaced, helical-shaped vanes 74 and 76 inannular spaces 30 and 28, respectively, proceed in a clockwisedirection, as noted by arrows 96 and 98, when looking along thelongitudinal axis of heat exchanger 10 in the direction indicated byarrow 94. Placing the helical-shaped vanes in such manner creates acounter flow or opposite flow be tween the fluids in adjacent annularspaces. Arrow 104 indicates the direction of fluid flow in annular space30 while arrow 106 indicates the direction of fluid flow in annularspace 28.

It is noted that the clockwise, counter-clockwise placements ofhelical-shaped vanes 70, 72, 74 and 76 illustrate methods of placementin annular spaces 24, 26, 28, 30, 32 and 34 of FIGS. 1, 2 and 3 ofhelicalshaped vanes to achieve various directions of flow between fluidsin the adjacent annular spaces. Wavesurfaced, helical-shaped vanes 74and 76 are sealed at their edges to the concentric cylinders, formingthe annular space in which they are disposed in like manner to vanes 70and 72 of FIG. 4.

It will be appreciated by those skilled in the art that the specificembodiment of FIG. 1 includes such suitable and necessary fluidicsealing means as to render the specific embodiment operable. Suchfluidic sealing means are not illustrated in FIGS. 1, 2, 3, 4 or 5.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described herein.

I claim:

1. A concentric tube heat exchanger for transferring heat from one fluidto another fluid comprising:

a. a cylindrical casing having a first and a second end;

b. a plurality of concentric cylinders located inside said cylindricalcasing, each pair of adjacent concentric cylinders having an annularspace therebetween, each said cylinder having a first and a second end;

c. a plurality of helical-shaped vanes having continuously wave shapedsurfaces contacting said fluid flowing thereby connected betweenadjacent concentric cylinders with one vane being disposed in each saidannular space, each said vane being attached to each of its respectiveconcentric cylinders along its entire length, said attachments providingfluid-tight seals with said concentric cylinders, said wave shapedsurfaces of said helical vanes imparting turbulence to heat exchangefluids flowing through said annular spaces;

d. first inlet means;

e. first outlet means;

f. second inlet means;

g. second outlet means;

h. first and second manifold means connected to the first and secondends, respectively, of said cylindrical casing and to said plurality ofconcentric cylinders for creating a first and a second fluidic paththrough said annular spaces, said first fluidic path being between saidfirst inlet means and said first outlet means, said second fluidic pathbeing between said second inlet means and said second outlet means, saidfirst fluidic path being formed by connecting every other annular spacein series, starting from the annular space adjacent to the outermostannular space and proceeding to the innermost annular space, said secondfluidic path being formed by connecting every other annular space inseries, starting from the outermost annular space and proceeding to theannular space adjacent the innermost annular space.

2. The concentric tube heat exchanger of claim 1 wherein said pluralityof helical-shaped vanes are disposed eounter-clockwise in the annularspaces of both said first and second fluidic paths, thereby creatingcounter-flow of fluids in adjacent annular spaces.

3. The concentric tube heat exchanger of claim 1' wherein said pluralityof helical-shaped vanes are disposed counterclockwise in the annularspaces defining said first fluidic path and clockwise in the annularspaces defining said second fluidic path, thereby creating crosscounter-flow of fluids in adjacent annular spaces.

l i I i

1. A concentric tube heat exchanger for transferring heat from one fluidto another fluid comprising: a. a cylindrical casing having a first anda second end; b. a plurality of concentric cylinders located inside saidcylindrical casing, each pair of adjacent concentric cylinders having anannular space therebetween, each said cylinder having a first and asecond end; c. a plurality of helical-shaped vanes having continuouslywave shaped surfaces contacting said fluid flowing thereby connectedbetween adjacent concentric cylinders with one vane being disposed ineach said annular space, each said vane being attached to each of itsrespective concentric cylinders along its entire length, saidattachments providing fluid-tight seals with said concentric cylinders,said wave shaped surfaces of said helical vanes imparting turbulence toheat exchange fluids flowing through said annular spaces; d. first inletmeans; e. first outlet means; f. second inlet means; g. second outletmeans; h. first and second manifold means connected to the first andsecond ends, respectively, of said cylindrical casing and to saidplurality of concentric cylinders for creating a first and a secondfluidic path through said annular spaces, said first fluidic path beingbetween said first inlet means and said first outlet means, said secondfluidic path being between said second inlet means and said secondoutlet means, said first fluidic path being formed by connecting everyother annular space in series, starting from the annular space adjacentto the outermost annular space and proceeding to the innermost annularspace, said sEcond fluidic path being formed by connecting every otherannular space in series, starting from the outermost annular space andproceeding to the annular space adjacent the innermost annular space. 2.The concentric tube heat exchanger of claim 1 wherein said plurality ofhelical-shaped vanes are disposed counter-clockwise in the annularspaces of both said first and second fluidic paths, thereby creatingcounter-flow of fluids in adjacent annular spaces.
 3. The concentrictube heat exchanger of claim 1 wherein said plurality of helical-shapedvanes are disposed counterclockwise in the annular spaces defining saidfirst fluidic path and clockwise in the annular spaces defining saidsecond fluidic path, thereby creating cross counter-flow of fluids inadjacent annular spaces.